All categories

3 years ago

Why does the picture on a tv screen become distorted when a magnet is brought near the screen

1 answer:

3 0

When a magnet is brought close to the picture tube, the interaction between the flying electrons and the magnetic field creates a force that throws the electrons off course. Now the electrons are hitting the screen in places they were not intended to strike and the picture becomes distorted.

When a television receives a signal, it first splits off the audio (sound) signal and the picture signal from a carrier wave (which is used to allow the signal to be transmitted over long distances). The audio is sent straight to the speakers to produce sound. The picture signal consists of three elements, red, green and blue. A standard television has three 'electron guns' at the back of the set, one for each colour. Let's start by looking at the red signal. The red signal is fed into one of these 'guns'. The gun produces a beam of electrons that varies in intensity with the strength of the red signal. This beam is fired towards the tv screen. The electron beam starts at the top-left of the screen and magnetic fields are used to 'sweep' this beam across the screen in parallel horizontal lines (if you look closely at a tv screen you can see these lines). UK televisions (PAL) have 625 lines and update the picture 25 times per second, US televisions (NTSC) have 525 lines but update 30 times per second. The back of the tv screen is covered in phosphor 'dots' (pixels) which glow when they are struck by these electrons. The red-signal electron beam is aimed so that it strikes phosphor dots that glow red, emitting photons which the eye can detect. The same process occurs for green and blue; each colour signal goes to one particular electron gun which excites just the dots of that colour, the signal tells the gun how strong it should be which in turn means some dots glow brighter than others. When you sit back from the tv screen, you don't notice the dots nor the flicker, your eye blends the image together to give a clear picture which appears to move. Now to answer the question! A magnet distorts the picture as it distorts the path of electrons flowing from the electron gun towards the screen inside the tv. As electrons are negatively charged particles, their motion is distorted by a magnet. So it is these electrons, not photons, which are distorted by the magnet. On older tvs, damage caused by holding a magnet too close to a tv could be permanent; newer tvs tend to have a demagnetisation process when you switch them on, to ensure that the picture is not permanently distorted. ehehe..

You might be interested in

To analyze the motion of a body that is traveling along a curved path, to determine the body's acceleration, velocity, and posit

DiKsa [7]

To solve this problem we will apply the kinematic equations of linear motion and centripetal motion. For this purpose we will be guided by the definitions of centripetal acceleration to relate it to the tangential velocity. With these equations we will also relate the linear velocity for which we will find the points determined by the statement. Our values are given as

$R = 350ft$

$a_t = 1.1ft/s^2$

PART A )

$a_c = \frac{V^2}{R}$

$a_c = \frac{V^2}{350}$

Calculate the velocity of the motorcycle when the net acceleration of the motorcycle is $5.25ft/s^2$

$a = \sqrt{a_t^2+a_r^2}$

$5.25 = \sqrt{(1.1)^2+(\frac{v^2}{350})^2}$

$27.5625 = 1.21 + \frac{v^4}{122500}$

$v=42.3877ft/s$

Now calculate the angular velocity of the motorcycle

$v = r\omega$

$42.3877 = 350\omega$

$\omega = 0.1211rad/s$

Calculate the angular acceleration of the motorcycle

$a_t = r\alpha$

$1.1 = 350\alpha$

$\alpha = 3.1428*10^{-3}rad/s^2$

Calculate the time needed by the motorcycle to reach an acceleration of

$5.25ft/s^2$

$\omega = \alpha t$

$0.1211 = 3.1428*10^{-3}t$

$t = 38.53s$

PART B) Calculate the velocity of the motorcycle when the net acceleration of the motorcycle is $6.75ft/s^2$

$a = \sqrt{a_t^2+a_r^2}$

$6.75 = \sqrt{(1.1)^2+(\frac{v^2}{350})^2}$

$45.5625 = 1.21 + \frac{v^4}{122500}$

$v=48.2796ft/s$

PART C)

Calculate the radial acceleration of the motorcycle when the velocity of the motorcycle is $21.5ft/s$

$a_r = \frac{v^2}{R}$

$a_r = \frac{21.5^2}{350}$

$a_r =1.3207ft/s^2$

Calculate the net acceleration of the motorcycle when the velocity of the motorcycle is $21.5ft/s$

$a = \sqrt{a_t^2+a_r^2}$

$a = \sqrt{(1.1)^2+(1.3207)^2}$

$a = 1.7187ft/s^2$

PART D) Calculate the maximum constant speed of the motorcycle when the maximum acceleration of the motorcycle is $6.75ft/s^2$

$a = \sqrt{a_t^2+a_r^2}$

$6.75 = \sqrt{(1.1)^2+(\frac{v^2}{350})^2}$

$45.5625 = 1.21 + \frac{v^4}{122500}$

$v=48.2796ft/s$

3 0

3 years ago

Social problems obstruct the development of society

aniked [119]

Answer:

This leads to backwardness and lagging in the development of the the society. Social problems such as sickness, poverty , social injustices , corruption , nepotism, tribalism are slowing down the process of development .

8 0

3 years ago

Which is a correct reason to physically connect objects with a bond wire when transferring flammable liquids? A. To create a pat

RideAnS [48]

<h2>When Transferring Flammable Liquids - Option A</h2>

To create a pathway for the liquid to flow easily is a correct reason to physically connect objects with a bond wire when transferring flammable liquids. Physically connect the two conductive objects together with a bond wire to eliminate a difference in static charge potential among them. The bond wire is attached between the containers in the process of flammable filling liquid actions except for a metallic path is found.

5 0

3 years ago

Read 2 more answers

A shooting star is actually the track of a meteor, typically a small chunk of debris from a comet that has entered the earth's a

s2008m [1.1K]

Answer:

A. Power generated by meteor = 892857.14 Watts

Yes. It is obvious that the large amount of power generated accounts for the glowing trail of the meteor.

B. Workdone = 981000 J

Power required = 19620 Watts

Note: The question is incomplete. A similar complete question is given below:

A shooting star is actually the track of a meteor, typically a small chunk of debris from a comet that has entered the earth's atmosphere. As the drag force slows the meteor down, its kinetic energy is converted to thermal energy, leaving a glowing trail across the sky. A typical meteor has a surprisingly small mass, but what it lacks in size it makes up for in speed. Assume that a meteor has a mass of 1.5 g and is moving at an impressive 50 km/s, both typical values. What power is generated if the meteor slows down over a typical 2.1 s? Can you see how this tiny object can make a glowing trail that can be seen hundreds of kilometers away? 61. a. How much work does an elevator motor do to lift a 1000 kg elevator a height of 100 m at a constant speed? b. How much power must the motor supply to do this in 50 s at constant speed?

Explanation:

A. Power = workdone / time taken

Workdone = Kinetic energy of the meteor

Kinetic energy = mass × velocity² / 2

Mass of meteor = 1.5 g = 0.0015 kg;

Velocity of meteor = 50 km/s = 50000 m/s

Kinetic energy = 0.0015 × (50000)² / 2 = 1875000 J

Power generated = 1875000/2.1 = 892857.14 Watts

Yes. It is obvious that the large amount of power generated accounts for the glowing trail of the meteor.

B. Work done by elevator against gravity = mass × acceleration due to gravity × height

Work done = 1000 kg × 9.81 m/s² × 100 m

Workdone = 981000 J

Power required = workdone / time

Power = 981000 J / 50 s

Power required = 19620 Watts

Therefore, the motor must supply a power of 19620 Watts in order to lift a 1000 kg to a height of 100 m at a constant speed in 50 seconds.

6 0

3 years ago

What is the wavelength of a wave with a frequency of 262 hz and a speed of 343 m/s

Tamiku [17]

Heya!!

For calculate wavelength, lets applicate formula:

$\boxed{\lambda = V/f}$

<u>Δ Being Δ</u>

f = Frequency = 262 Hz

v = Velocity = 343 m/s

$\lambda$ = Wavelenght = ?

⇒ Let's replace according the formula:

$\boxed{\lambda = 343\ m/s / 262\ Hz }$

⇒ Resolving

$\boxed{\lambda = 1,3 \ m}$

Result:

The wavelength is <u>1,3 meters.</u>

Good Luck!!

8 0

3 years ago

Read 2 more answers

Why does the picture on a tv screen become distorted when a magnet is brought near the screen​

Why does the picture on a tv screen become distorted when a magnet is brought near the screen